U.S. patent number 6,009,491 [Application Number 08/876,404] was granted by the patent office on 1999-12-28 for data transmission method having a data line which is separate from a data bus and is designed as a chain.
This patent grant is currently assigned to Robert Bosch GmbH. Invention is credited to Jurgen Althoff, Detlef Rode, Rudiger Roppel.
United States Patent |
6,009,491 |
Roppel , et al. |
December 28, 1999 |
**Please see images for:
( Certificate of Correction ) ** |
Data transmission method having a data line which is separate from
a data bus and is designed as a chain
Abstract
A method for controlling the transmission of information between
electronic components in a motor vehicle, which components can be
either data sources or data sinks, in which a cascade design is
used to facilitate the transmission of information. By separating
the control signal from the actual streams of data, a flexible,
chain type of structure is obtained.
Inventors: |
Roppel; Rudiger (Hildesheim,
DE), Rode; Detlef (Hemmingen, DE), Althoff;
Jurgen (Braya, PT) |
Assignee: |
Robert Bosch GmbH (Stuttgart,
DE)
|
Family
ID: |
7797413 |
Appl.
No.: |
08/876,404 |
Filed: |
June 16, 1997 |
Foreign Application Priority Data
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Jun 20, 1996 [DE] |
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196 24 528 |
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Current U.S.
Class: |
710/305; 307/149;
327/142; 710/107; 710/21; 710/65 |
Current CPC
Class: |
H04Q
9/00 (20130101) |
Current International
Class: |
H04Q
9/00 (20060101); G06F 013/40 () |
Field of
Search: |
;395/822,287,309,841
;307/149 ;327/142 ;210/2,21,65,129,107,128 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lee; Thomas C.
Assistant Examiner: Kim; Harold
Claims
We claim:
1. Method for controlling the transmission of information between
electronic components, preferably in a motor vehicle, which either
supply information or process it and which are connected linearly
to each other and also to a controlling component via a data bus,
said method comprising
actively connecting a component for transmitting the information
and least one component for processing the information by the
controlling component, and
feeding the information into a data line, which is separate from
the data bus and connects all the components to each other wherein
the data line is designed as a chain, such that data are sent along
the chain via bypass circuits.
2. Method for controlling the transmission of information according
to claim 1 wherein the data line transmits information which is in
analog and/or digital form.
3. Method for controlling the transmission of information according
to claim 1 wherein standard communications protocols are used for
the transmission of information between two components via the data
line.
4. Method for controlling the transmission of information according
to claim 1 wherein the information is transmitted serially from
point to point by means of self-timed encoding.
5. Method for controlling the transmission of information according
to claim 1 wherein the information is transmitted in the standard
S/P-DIF format.
6. Method according to claim 1 wherein components which are not end
components have a bypass circuit with an input connection and an
output connection to the data line and also a connection to the
functional unit (transmitting or processing unit) , which, upon
activation, is connected either to the output or to the input
depending on the function.
7. Method according to claim 6 wherein the components which are end
components have an input or an output with a connection to the
functional unit.
8. Method according to claim 6 wherein digital information is sent
without clock regeneration through the bypass circuit, where
switching can be carried out by either electrical or optical
means.
9. Method according to claim 6 wherein the data line is a plastic
fiber-optic waveguide, and in that the data inputs and outputs are
connected to the electrical circuit by way of optocouplers.
10. Method according to claim 6 wherein the component has a
connection to the control line via a microcomputer and a bus
interface.
11. Method according to claim 6 wherein the control line is
realized by a CAN bus.
12. Method according to claim 6 wherein the components are
controlled by a separate control component.
13. Method according to claim 6 wherein the control function is
integrated into a component.
14. Apparatus for controlling the transmission of information
between electronic components, said apparatus comprising:
a transmitting component for transmitting information;
at least one processing component for processing information;
a controlling component;
a data bus actively connecting said transmitting component, said at
least one processing component, and said controlling component, and
a data line which is separate from the data bus and connects all
the components together and is designed as a chain, with data being
sent along the chain via bypass circuits.
15. Apparatus according to claim 14 wherein the data line transmits
information which is in analog and/or digital form.
16. Apparatus according to claim 14 wherein standard communications
protocols are used for the transmission of information between two
components via the data line.
17. Apparatus according to claim 14 wherein the information is
transmitted serially from point to point by means of self-timed
encoding.
18. Apparatus according to claim 14 wherein the information is
transmitted in the standard S/P-DIF format.
Description
BACKGROUND OF THE INVENTION
The invention proceeds from a method for controlling the
transmission of data between electronic components, preferably in a
motor vehicle, which either supply information or process it, and
which are linearly connected to each other and to a controlling
component by a data bus.
Methods for controlling the transmission of data between electronic
components in a motor vehicle are already known, i.e., methods
which help solve the problem of finding space for motor vehicle
components which provide information and entertainment by
increasing their functionality and complexity in spite of the high
level of their integration. This approach leads to networked
systems and decentralized components. It is necessary not only to
control and monitor information but also to transmit audio and
video data as well as possibly the data stored on a CD-ROM (called
"data" or "useful data" in the following). A modular concept, which
allows the data to be transmitted over coaxial cables or
fiber-optic waveguides, usually made of plastic, is required for
the transmission of these data. For cost reasons, standard
communications protocols are used for these transmissions.
A networking of components in motor vehicles in the form of a star
topology is known. In this design, several data sources are
connected to a data sink. The number of these sources cannot be
exceeded by the limited number of free inputs. In addition, a large
amount of space is required, and the large number of plug contacts
which the data sink must have is also disadvantageous.
Optical ring structures are also known, in which both data and
control/monitoring information are transmitted over the
transmission medium. Each component, whether data source or data
sink, has an optoelectronic converter at its input and an
electro-optic converter at its output. A protocol processor makes
it possible for the data to be read in and out. In a ring
structure, the data stream must be clocked. The disadvantage of a
ring topology and of the transmission of all the data over the same
medium is the fact that a break at any point puts the entire
network out of service. Components in a ring structure which have
no data burden of their own beyond information for control and
monitoring, e.g., remote controls, have an oversized interface.
SUMMARY OF THE INVENTION
According to the invention, a component for transmitting
information and at least one component for processing information
are actively connected by the controlling component. Information is
fed into a data line which is separate from the data bus and
connects all the components together.
The invention offers the advantage that pure data transmission is
disconnected from the control and monitoring function, in that the
control lines and the data lines are connected separately to the
components of the network. As a result, a simple cascade structure
of the components is obtained, in which the sequence of components
in the chain is arbitrary and in which the number of components is
not restricted by the number of plug-in locations. A break in the
data line leads to the loss of the data of the components which are
on the other side of the break with respect to the data source, but
the rest of the components continue to work normally. The two
components serving as the source and the sink of information are
actively connected by way of the control bus.
In a cascaded design, it is advantageous that the data line passes
by way of bypass circuits through the individual networked
components which are not end components. This offers the advantage
that a simple circuit unit does the job of connecting the
components, and there is no need actively to generate clock pulses
with a phase-locked loop. Thus the electronic complexity of a
component of the data network is reduced.
Because of the simple design of the connection, it is possible to
transmit digital and/or analog data; the system can thus be
upgraded to meet increasing requirements. Standard communications
protocols and methods can be used. For example, the use of the
S/P-DIF protocol for digital data transmission with self-timed
encoding is advantageous.
It is advantageous for the components used to implement the method
to have a bypass circuit with a simple switch, which connects the
output and the input of the component to the functional unit.
It is also advantageous for the data sources which are used as end
components to have only a data output, which means that there is no
need for a bypass circuit. End components which work as data sinks
require only a data input.
The data cascade is advantageously controlled by way of a control
line, which is connected to a microcomputer and to a bus interface
at each component. It is advantageous for the control line to be
realized as a CAN (Controller Area Network) bus, and the control
component can either be a separate unit or be integrated into some
other component.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a linear network system according to the
invention.
FIG. 2 shows how bypass circuits are used to create a chain.
FIG. 3 shows the design of a transmission component in the data
cascade.
FIG. 4 shows the design of a receiving component in the data
cascade.
FIG. 5 shows an exemplary embodiment of the data transmission
system.
DESCRIPTION OF THE EXEMPLARY EMBODIMENT
FIG. 1 shows the most general form of a network of components. The
network system according to the invention assumes that the control
and monitoring data are separated in a communications sense from
the useful data. The data are transmitted over data lines 3. The
transmission itself is advantageously based on a digital
communications protocol, which uses self-timing encoding. Encoding
of this type is, for example, biphase mark encoding, which makes
possible the synchronous transmission of data over line 3. Of
course, the cascade according to the invention can also transmit
analog signals such as audio-NF.
Control occurs via the MMI master (Man-Machine Interface) 8. This
master 8 is responsible for controlling the cascade. The master can
be an independent component as shown in FIG. 1, or it can be
integrated into any one of the components of the data cascade. The
master represents the interface with the user. An MMI master
monitors and stores all conditions which are relevant to the
networking of the data. If nonvolatile memory (e.g., an EEPROM) is
used to store the cascade conditions, then in the case of an audio
cascade, for example, the last source which was listened to before
the system was turned off will be heard when the system is turned
back on again. Master 8 is connected via data line 5 to the
individual components of the data cascade. In this embodiment, a
data source 1 and a data sink 2 are present initially in each
component. Switch 13 connects the function selected by control unit
8 via an input/output to data line 3.
FIG. 2 shows a special embodiment which makes it easier to connect
the components to the data line and thus simplifies their
replacement. Components 9 each represent either a data source 1 or
a data sink 2, but a component with pure control functions is also
shown. Within a cascade, each component 9 has a data output 12 and
a data input 11 intermediaries 14 and 15. The two inputs and
outputs are wired to source 1 by means of a bypass 10. The end
components can be data sources, which in that case have only a data
output 12. Components 9 which are not data sources or data sinks
and which only make control information available are connected to
control bus 5. In general, a data sink is found at the end of the
cascade. Data sources and data sinks contain all the necessary
sending and receiving interfaces. If there is only one data sink,
the sequence of components in the data cascade is arbitrary.
FIG. 3 shows the design of a component 9 with a data source 1.
Control and monitoring bus 5 is connected in the component to a bus
interface 16, which is controlled by a microprocessor. Data source
1 with its encoding circuit communicates via the microprocessor
system with the control unit. Component 9 also has a bypass circuit
10. Input 11, which in this case is connected to a fiber-optic
waveguide, must be provided with an opto-electronic converter 14.
Switch 13 can connect input 11 to output 12 via an additional
opto-electronic converter 15. In addition to the bypass on an
electrical plane described in this exemplary embodiment, there is
switch for the bypass function.
FIG. 4 shows a circuit for use with a data sink not installed as an
end component; the circuit therefore also has a bypass. In general,
the MMI master activates the source such as a CD changer and the
data sink by sending commands over the control bus.
In the case of a navigation device, data source 1 informs the
master of the data cascade via control and monitoring bus 5 that
driving instructions are available and that the data are ready for
transmission to the data sink. The instruction actively to connect
this data source arrives over the control and monitoring bus. Then
switch 13 to the data source is flipped, and the signals of the
data source pass via electro-optic converter 15 to output 12 and
data line 3. There is never more than one source active in the
cascade; all the other components pass the data stream through
their bypass circuits 10. An essential feature of the bypass
circuit is its design as a simple circuit component which allows
the data stream to pass through without clock regeneration. The
number of maximum allowable components in a data cascade is
determined by the quality of transmission lines 3 and interface
circuits 14, 15. When suitable fiber-optic waveguide systems, e.g.,
plastic fiber-optic waveguides, and interface circuits are used, up
to 10 components can be connected in the cascade.
Relative to the cascading of the components, four different types
of components 9 can be distinguished:
(a) Data sinks (end components): The data sink has only an input
11. In principle, several data sinks are possible in a cascade. As
a result, however, the networking sequence is no longer
arbitrary.
(b) Cascadable data sources: Each component has a data input 11 and
a data output 12. In addition, a bypass circuit 10 is integrated
into the component; this circuit consists essentially of a two-way
switch, made according to CMOS technology, for example, with two
positions: internal source active/arbitrary external source active.
The position of the switch is monitored by the microprocessor
system with its bus interface and controlled by MMI master 8 over
control and monitoring bus 5. If there is a problem with the bus
interface, the switch is automatically shifted back to the default
setting, namely, pass-through.
(c) Noncascadable data source (end component): An end component has
only a data output 12. Precisely one end component can be present
in each system. Whether a component is designed as an end component
or not depends in general on the configuration probability and the
probable installation site.
(d) Components which do not process data within the cascade:
Components which have no connection for a data cascade can still be
operated in the network by way of control and monitoring bus 5.
In principle, the cascade is suitable both for coaxial cables and
for fiber-optic waveguides. In both cases, an interface circuit
(e.g., potential separation, signal conversion from optical to
electrical, etc.) is required. In the cascade, the same
communications protocol should be used for all of the components,
but in the case of audio transmission, different sampling rates can
be present in the components. The allowable sampling rates depend
only on the communications protocol used and on the PLL range of
the data sink. If different communications protocols are used
within a cascade, the sink must be designed to handle all the
protocols used, at additional expense.
FIG. 5 shows a concrete embodiment of a network in an automobile.
On dashboard A of the motor vehicle there is a voice output 20,
integrated into a radio device, for example, and a telephone
output/input unit 21. These two data sinks are connected via a
control bus 5 to the components installed in the trunk. Components
for which no direct user input is required are installed in the
trunk of the vehicle. In the present example, these can be
navigation devices 22 and a CD changer 23. The data of the
components are transmitted by way of fiber-optic waveguides 3 to
the data sink, in this case voice output 20, which also contains
the MMI. The controller area network (CAN) is used as a basis for
the control and monitoring bus. The audio data themselves are sent
over the data line, i.e., the fiber-optic waveguide cascade. The
communications protocol for the audio data is, for example, an
S/P-DIF protocol, which means that a stereo channel is
available.
The data cascade can also be used in the home for multimedia
applications. Any desired system configurations are conceivable for
this purpose. In principle, the data cascade is also suitable for
video applications, especially when compression and transmission
methods such as MPEG are available.
* * * * *